It has long been recognized that the presence of moisture furnishes a cool, comparatively smooth smoke. It has also been suggested that the presence of moisture acts to condense some of the tars in the stream of tobacco smoke.
There is presently on the market a product called "Aqua Filter" which comprises a cigarette holder containing a filter or cartridge which is prewet with a fluid containing water. In order that the fluid or water shall not evaporate between the time of manufacture and the time of use, the reservoir, container or cigarette holder having the filter therein has its ends sealed by an insert at the cigarette end and a plastic top at the mouthpiece end. These parts must be removed at the time the holder is used for the smoking of a cigarette. Also, the manufacturer recognizes that the seal provided at each end of the holder may not be effective, and it is suggested that if some of the moisture has evaporated when the product is ready for use, the filter insert may be re-moistened by putting the large end under a faucet. It will be apparent that it is essential to provide suitable means for sealing in order not to lose the fluid or moisture by evaporation or otherwise. The provision of the sealing means involves the cost of the parts and the cost of assembling the parts with the cigarette holder. Moreover, according to one of the patents pertaining to the product described above (U.S. Pat. No. 3,048,180), filter tips integral with the cigarettes cannot of necessity be readily formed as hygroscopic filters. The product described above and in the aforementioned patent is considered a hygroscopic filter.